With the development of the Internet, a requirement on interface bandwidth of the Ethernet increases. The interface bandwidth of the Ethernet increases from 10 gigabits per second (Gigabit per second, Gpbs) to 100 Gbps, and evolves towards 400 Gbps and 1 terabit per second (terabit per second, Tbps). To improve channel utilization, a flexible grid optical transmission network (Flexible Grid Optical Transmission Network) technology emerges. An optical layer of an Ethernet interface can dynamically adjust a data sending rate according to a transmission distance of to-be-transmitted data and quality of a channel used to transmit the data. An interface standard of a network device may be 10 Gbps, 40 Gbps, or 100 Gbps. To implement interconnection, interfaces of two communication parties need to use interface standards that match each other. To reduce hardware costs, a design requirement that a transmitter or a receiver includes Ethernet interfaces of different interface standards exists. In the foregoing scenario, a variable-bandwidth interface needs to be used. A variable-bandwidth optical layer technology also requires that an electrical layer should include a variable-bandwidth interface.
In an Ethernet communication protocol, to ensure normal working of a clock and data recovery (Clock Data Recover, CDR) circuit, a scramble algorithm is generally used, so as to reduce a probability that successive 0s or successive 1s appear in transmitted serial data.
In the prior art, a scrambling apparatus can only scramble a data stream of a specification, and cannot scramble a data stream of another specification. A usage scenario of the scrambling apparatus is limited. For example, a requirement of a flexible Ethernet scenario cannot be well satisfied. For example, in the prior aft, if a scrambling apparatus is configured to scramble a data stream formed by two sub-data streams, the scrambling apparatus can only scramble a data stream formed by two sub-data streams, and cannot be configured to scramble a data stream formed by three sub-data streams, and cannot scramble a data stream including only one sub-data stream either.